American “Ninja” Eels Climb Dams to Live

American eels need to migrate from the Sargasso Sea in the Atlantic Ocean into rivers, but dams along the eastern coast stop them cold. One solution on the Roanoke River allows them to climb into traditional feeding grounds—kind of like a reality show obstacle course.

Young eels enter the Roanoke River in North Carolina after being carried by ocean currents. Their journey remains free of physical barriers until reaching the Roanoke Rapids Dam near the Virginia border. Owned by Dominion Power and built in 1955, the 3,050-foot-long concrete dam is used for hydropower. Eels were not able to pass the dam for decades.

But in 2010, as part of the dam’s renewed license from the Federal Energy Regulatory Commission, NOAA Fisheries collaborated with local partners to have the Commission require Dominion Power to install two eel passage structures, called “eelways.” These structures are long, sloping ramps with a peg board of pipes to allow the eels to wriggle up and over the dam. A slow trickle of water encourages the eels as they make the climb. Since 2010, more than two million eels have migrated upstream into 29 miles of historic habitat.

Next steps include optimizing operation of the eelways to increase their efficiency and monitoring eel numbers in the various habitats above the Roanoke Rapids Dam to determine when it will be necessary to begin protecting eels migrating downstream during their return to the Sargasso Sea to reproduce. The monitoring will also help determine when an eelway is needed for Gaston Dam, the next dam upstream and blocking over 100 miles of eel habitat. American eels promote a healthy ecosystem in the Roanoke River as well as Albemarle Sound where many of the fish that are part of commercial or recreational fisheries feed upon American eels.

Habitat access is essential to support the life cycle and help recover the population of American eels, currently at historically low levels and recently the subject of two petitions for protection under the Endangered Species Act. Other locations in the Southeastern U.S. where NOAA Fisheries is currently helping American eels return to blocked river habitat include the Sabine River along the Texas/Louisiana border and the Santee River Basin in South Carolina.

A staircase for eels parallels the human
staircase at Roanoke Rapids Dam.
 


(Photo: Bob Graham, Dominion Power)
A close-up view of the Roanoke Rapids Dam
eelway shows young American eels climbing
PVC pipe.


(Photo: Bob Graham, Dominion Power)
A net of young American eels, called elvers.



(Photo: Bob Graham, Dominion Power)